1. Field of the Invention
The present invention relates to a method, computer storage device, and tone control device for generating tones with a vibrato effect.
2. Description of the Related Art
Electronic musical instruments such as synthesizers and the like can generate tones with various kinds of tone colors. When performance of a natural musical instrument is imitated by an electronic musical instrument, it is necessary to make the tone colors to be faithfully imitated to tone colors of the natural musical instrument. In addition, the performer needs to understand the characteristic peculiar to the musical instrument and needs to perform while operating user interfaces of the musical instrument (such as, for example, the keyboard, the pitch-bend lever, the modulation lever, the HOLD pedal and the like) during his or her performance. Therefore, when the performer attempts to imitate performance of a certain musical instrument, using an electronic musical instrument, the performer needs to have good understanding of the characteristic of the musical instrument to be imitated, and is required to have high-level skills in performance technique to make full use of the user interfaces according to the characteristic during performance.
For example, when the vibrato effect is added to tones, the LFO (Low Frequency Oscillator) depth in pitch and level is assigned to the user interfaces such as a modulation lever. The performer manually operates the user interfaces according to the performance state, thereby adjusting the amount of vibrato. Therefore, for adding the vibrato effect, the performer needs to have high-level performance skills.
In this respect, in recent years, electronic musical instruments automatically add the vibrato effect to tones according to the state of performance. Among those electronic musical instruments, there is an electronic musical instrument that variably controls the amount of vibrato according to velocity. However, these electronic musical instruments add the vibrato effect for a single note even in polyphony performance. Therefore, when performance of a solo musical instrument that is capable of polyphony, such as, a violin is imitated, the performance would sound artificial. One of the reasons for this artificiality is that for a solo musical instrument capable of polyphony, such as, a violin, when the performer plays polyphonic notes, vibrato added for a single note tends not to be added for polyphonic notes due to the structural problem of the musical instrument.
Japanese Patent Publication No. JP2199500 describes an electronic musical instrument that is capable of changing the effect according to the number of keys depressed, when the tone color of a piano is selected.